An interferometer direction finding system staggered baseline arraying method

Abstract

This application belongs to the technical field of staggered baseline arraying for interferometer direction finding systems, specifically relating to a method for staggered baseline arraying in an interferometer direction finding system, including: calculating the shortest length L of a long baseline. sL ; Calculate the basic line element length d0; Design the staggered baseline length as: d i =n i d0, i = 1, 2, ..., M; n M >…>n2>n1≥D / d0,n1,n2,…,n M Pairwise coprime; n M ≥L sL / d0; when i>1, n i -n i‑1 ≥D / d0; where d i The length of the i-th staggered baseline; M is the number of staggered baselines; n i is the coefficient of the i-th staggered baseline; D is the minimum spacing between line elements.

Description

Technical Field

[0001] This application belongs to the field of staggered baseline array technology for interferometer direction finding systems, and specifically relates to a staggered baseline array method for interferometer direction finding systems. Background Technology

[0002] An interferometer direction finding system measures the phase difference between two line element signals that form a baseline, converts the phase difference information into the angle of arrival, and obtains the radiation source angle information, thus realizing the direction finding of the radiation source.

[0003] The direction finding accuracy of an interferometer direction finding system is directly proportional to the baseline length. The longer the baseline, the higher the direction finding accuracy. However, the phase difference is a function with a period of 2π. If the baseline length is too large, the phase difference will exceed the period, which will cause the phase ambiguity problem of the interferometer direction finding system.

[0004] Currently, the main defuzzification algorithms used are long and short baseline defuzzification algorithm, virtual baseline defuzzification algorithm, and staggered baseline defuzzification algorithm, which are employed to defuzzify the phase ambiguity of the interferometer direction finding system.

[0005] The long and short baseline deblurring algorithm requires that there must be a baseline length that meets the unblurred range. However, due to the limitations of line element size and the consideration of the mutual coupling effect between line elements, it is usually difficult to meet the installation conditions of the shortest baseline.

[0006] The virtual baseline deblurring algorithm calculates the distance between adjacent short baselines by subtracting the length of the long baseline from the length of the short baseline, which is the virtual baseline. The phase difference between two adjacent distances is then used to obtain the corresponding virtual baseline phase difference. This deblurring method can overcome the limitation that the length of the short distance cannot be greater than half the wavelength and can process broadband signals. However, the length of the virtual baseline after subtracting the two baselines needs to be less than half the wavelength corresponding to the maximum frequency. In order to achieve correct deblurring, the length of the second longest baseline is limited to a certain value, which requires more array elements to assist in deblurring and puts greater pressure on the system's hardware overhead.

[0007] The staggered baseline deblurring algorithm can overcome the limitations of long and short baseline deblurring algorithms and virtual baseline deblurring algorithms in terms of array layout to a certain extent, and the array layout can be more flexible. However, it has high requirements for the array layout of staggered baselines, especially for high-frequency broadband radiation sources. The quality of the staggered baseline array layout will directly affect whether the phase ambiguity can be correctly resolved. At present, there is a lack of reliable methods to guide this.

[0008] This application is made in view of the aforementioned technical deficiencies.

[0009] It should be noted that the above background information is only used to assist in understanding the inventive concept and technical solution of this invention, and it does not necessarily belong to the prior art of this patent application. In the absence of clear evidence that the above information was disclosed on the filing date of this application, the above background information should not be used to evaluate the novelty and inventiveness of this application. Summary of the Invention

[0010] The purpose of this application is to provide a method for staggered baseline arraying in an interferometer direction finding system to overcome or mitigate at least one of the known technical defects.

[0011] The technical solution of this application is:

[0012] A method for staggered baseline arraying in an interferometer direction finding system, comprising:

[0013] Calculate the shortest length L of the long baseline sL ;

[0014] Calculate the basic line element length d0;

[0015] The design staggered baseline length is:

[0016] d i =n i d0, i = 1, 2, ..., M;

[0017] n M >…>n2>n1≥D / d0,n1,n2,…,n M Pairwise coprime;

[0018] n M ≥L sL / d0;

[0019] When i>1, n i -n i-1 ≥D / d0;

[0020] in,

[0021] d i Let be the length of the i-th staggered baseline;

[0022] M represents the number of staggered baselines;

[0023] n i The coefficient of the i-th uneven baseline;

[0024] D is the minimum spacing between line elements.

[0025] According to at least one embodiment of this application, in the above-described method for staggered baseline arraying of an interferometer direction finding system, the calculation of the shortest length L of the long baseline is... sL Specifically:

[0026]

[0027] in,

[0028] c is the speed of light;

[0029] f min This represents the lower limit of the radiation source frequency band range.

[0030] Δφ c The phase of the receiving channel in the interferometer direction finding system is inconsistent;

[0031] SNR is the signal-to-noise ratio of the interferometer direction-finding system.

[0032] θ is the upper positive limit of the angular range of the interferometer direction finding system relative to the radiation source;

[0033] Δθ represents the accuracy of the interferometer direction-finding system in measuring the angle of the radiation source.

[0034] This refers to the relative error in frequency measurement.

[0035] This represents the relative error in the spacing between line elements.

[0036] According to at least one embodiment of this application, in the above-described method for staggered baseline arraying of an interferometer direction finding system, the calculation of the basic line element length d0 specifically involves:

[0037]

[0038] in,

[0039] c is the speed of light;

[0040] f max This represents the upper limit of the radiation source frequency band range;

[0041] θ is the upper positive limit of the angular range of the interferometer direction finding system relative to the radiation source.

[0042] This application has at least the following beneficial technical effects:

[0043] A method for staggered baseline arraying in an interferometer direction finding system is provided. The design, based on the calculated minimum length of the long baseline and the length of the basic line elements, determines the range of staggered baseline coefficients by combining the minimum spacing of the line elements, and determines reasonable values ​​for the staggered coefficients to obtain the length of the staggered baseline. Based on this, a staggered baseline de-ambiguity algorithm is used to de-blur the phase ambiguity of the interferometer direction finding system, exhibiting a very high de-ambiguity probability. The minimum length of the long baseline and the length of the basic line elements can be calculated based on the radiation source frequency band range, the relative error of radiation source frequency measurement, the radiation source angle range, the radiation source angle measurement accuracy, the relative error of the line element spacing, the phase inconsistency of the receiving channel of the interferometer direction finding system, and the signal-to-noise ratio. Attached Figure Description

[0044] Figure 1 This is a schematic diagram of the staggered baseline array method for the interferometer direction finding system provided in the embodiments of this application.

[0045] To better illustrate this embodiment, some parts in the accompanying drawings may be omitted, enlarged, or reduced, and do not represent the actual size of the product. Furthermore, the accompanying drawings are for illustrative purposes only and should not be construed as limiting this patent. Detailed Implementation

[0046] To make the technical solution and advantages of this application clearer, the technical solution of this application will be described in a clearer and more complete manner below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only some embodiments of this application, and are only used to explain this application, not to limit this application. It should be noted that, for ease of description, only the parts related to this application are shown in the accompanying drawings. Other related parts can be referred to the general arrangement. In the absence of conflict, the embodiments and technical features in the embodiments of this application can be combined with each other to obtain new embodiments.

[0047] Furthermore, unless otherwise defined, the technical or scientific terms used in this application description shall have the ordinary meaning understood by one of ordinary skill in the art to which this application pertains. The terms "upper," "lower," "left," "right," "center," "vertical," "horizontal," "inner," and "outer," etc., used in this application description to indicate relative direction or positional relationship are used only to indicate relative orientation or positional relationship, and do not imply that the device or component must have a specific orientation, or be constructed and operated in a specific orientation. When the absolute position of the described object changes, its relative positional relationship may also change accordingly, and therefore should not be construed as a limitation on this application. The terms "first," "second," "third," and similar terms used in this application description are used only for descriptive purposes to distinguish different components, and should not be construed as indicating or implying relative importance. The terms "a," "one," or "the," etc., used in this application description should not be construed as an absolute limitation on quantity, but should be construed as indicating the existence of at least one. The terms "including," "comprising," etc., used in this application description mean that the element or object preceding the word covers the element or object listed after the word and its equivalents, without excluding other elements or objects.

[0048] Furthermore, it should be noted that, unless otherwise explicitly specified and limited, terms such as “installation,” “connection,” and “linkage” used in the description of this application should be interpreted broadly. For example, a connection can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; or it can be a connection within two components. Those skilled in the art can understand its specific meaning in this application according to the specific circumstances.

[0049] Lu Anan, Radio Direction Finding Theory and Engineering Practice [M], Beijing: Electronic Industry Press, 2020, 9-1, proves that:

[0050] If d i =n i d0,n i ∈Z, i=1,2,L,N, and the greatest common divisor (n1,L,n) N If ) = 1, then when -π / 2 < θ ≤ π / 2, the vector The necessary and sufficient condition for θ to be one-to-one is d0 / λ<1 / 2. For details, please refer to Lu Anan, Long baseline combination solution of direction finding ambiguity [J]. Mathematics in Practice and Theory, 2008, 38(10): 89-96.

[0051] The maximum unambiguous direction-finding angle of the interferometer direction-finding system can be derived. L is the longest baseline length;

[0052] Interferometer direction finding accuracy The angle measurement range is ±θ, and △φ is the phase error;

[0053] △φ c The phase error, Δφ, is caused by channel phase mismatch due to channel phase inconsistency. n The phase error is caused by internal noise.

[0054] Based on the above embodiments of this application, a method for staggered baseline arraying of an interferometer direction finding system is provided below, in conjunction with the appendix. Figure 1 For further detailed explanation of this application, please refer to the following:

[0055] Calculate the shortest length L of the long baseline sL Specifically:

[0056]

[0057] in,

[0058] c is the speed of light;

[0059] f min This represents the lower limit of the radiation source frequency band range.

[0060] Δφ c The phase of the receiving channel in the interferometer direction finding system is inconsistent;

[0061] SNR is the signal-to-noise ratio of the interferometer direction-finding system.

[0062] θ is the upper positive limit of the angular range of the interferometer direction finding system relative to the radiation source;

[0063] Δθ represents the accuracy of the interferometer direction-finding system in measuring the angle of the radiation source.

[0064] This refers to the relative error in frequency measurement.

[0065] This represents the relative error in the spacing between line elements.

[0066] The basic line element length d0 is calculated as follows:

[0067]

[0068] in,

[0069] f max This represents the upper limit of the radiation source frequency band range;

[0070] θ is the upper positive limit of the angular range of the interferometer direction finding system relative to the radiation source.

[0071] The design staggered baseline length is: d i =n i d0, i = 1, 2, ..., M;

[0072] n M >…>n2>n1≥D / d0,n1,n2,…,n M Pairwise coprime;

[0073] n M ≥L sL / d0;

[0074] When i>1, n i -n i-1 ≥D / d0;

[0075] in,

[0076] d i Let be the length of the i-th staggered baseline;

[0077] M represents the number of staggered baselines;

[0078] n i The coefficient of the i-th uneven baseline;

[0079] D is the minimum spacing between line elements.

[0080] In one specific embodiment, the radiation source is 6–18 GHz, θ = ±60°, and the system specifications include a signal-to-noise ratio (SNR) of 13 dB, a direction-finding accuracy of Δθ = 2°, an angle measurement range of θ = ±60°, a channel phase inconsistency of Δφ = 10°, and a line element spacing error of [missing information]. The frequency difference Δf / f = 0.3% is measured. A 6-18 GHz planar helical antenna with a diameter of 25 mm is selected. Considering the effects of mutual coupling, the shortest spacing between line elements is D = 30 mm. The speed of light is c = 3e8 m / s. The required number of line elements is M+1, and the number of baselines is M.

[0081] Calculate the shortest length L of the long baseline sL =132.4mm;

[0082] The basic line element length d0 is calculated to be ≤9.62mm, so we take d0=9.5mm;

[0083] Calculate the range of the unbalanced baseline coefficients. For values ​​that meet the conditions, M = 3, n1 = 4, n2 = 9, and n3 = 14 can be selected.

[0084] The staggered baseline lengths are: d1 = n1d0 = 4 * 9.5 = 38 mm, d2 = n2d0 = 9 * 9.5 = 85.5 mm, d3 = n3d0 = 14 * 9.5 = 133 mm

[0085] Through simulation verification (MATLAB signal-level simulation) of the staggered baseline de-ambiguity algorithm of the broadband interferometer direction finding system, under the above-mentioned signal-to-noise ratio, phase error and other conditions, it can effectively achieve phase ambiguity removal and obtain the correct target angle value. The statistically obtained angle measurement error is much smaller than the direction finding accuracy setting value.

[0086] The various embodiments in the specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0087] The technical solution of this application has been described in conjunction with the preferred embodiments shown in the accompanying drawings. Those skilled in the art should understand that the scope of protection of this application is obviously not limited to these specific embodiments. Without departing from the principles of this application, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of this application.

Claims

1. An irregular baseline arrangement method for an interferometer direction finding system, characterized in that, Comprising: Shortest length of a computed long baseline ; Computing basic line element length ; Design staggered baseline length is: ， ； , relatively prime ； In time, ; wherein, For the first The length of the first is the number of staggered baselines; is the first baseline coefficient; and is the second staggered baseline coefficient. Minimum distance for line elements; The shortest length of the calculated long baseline In particular: ； wherein, c is the speed of light; is the lower limit of the frequency range of the radiation source; Phase inconsistencies for interferometer direction finding system receive channels; signal-to-noise ratio for interferometer direction finding systems; To the upper limit of the angular range of the interferometer direction finding system for a radiation source; To improve the angular measurement accuracy of a radiating source by an interferometer direction-finding system; Relative error of frequency measurement for interferometer direction finding system; for line element spacing relative error; The computing basic line element length In particular, ； wherein, wherein, c is the speed of light; is the upper limit of the frequency range of the radiation source; The upper limit of the angular range of the radiation source is determined for the interferometer direction finding system.

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